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Year : 2023 | Volume
: 66
| Issue : 2 | Page : 438-440 |
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Catechism (Quiz 19) |
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Nermeen Chaudhry, Bindu Challa, Anil Parwani
Department of Pathology, Ohio State University Wexner Medical Center, Columbus, OH, USA
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Date of Submission | 19-Nov-2021 |
Date of Acceptance | 22-Nov-2021 |
Date of Web Publication | 17-Apr-2023 |
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How to cite this article: Chaudhry N, Challa B, Parwani A. Catechism (Quiz 19). Indian J Pathol Microbiol 2023;66:438-40 |
A 40-year-old male with a history of focal segmental glomerulosclerosis (diagnosed at 15 years of age) complicated by end-stage renal disease presented with abdominal pain after peritoneal dialysis. MRI abdomen without contrast showed 2.6 cm × 3.6 cm complex cystic mass in interpolar right kidney and 1.9 cm × 1.6 cm complex cystic mass in lateral mid to lower pole of left kidney. Patient subsequently underwent bilateral radical nephrectomy. Microscopic images are provided in [Figure 1] and [Figure 2].
- What is the diagnosis?
- What is the differential diagnosis?
Answers of Catechism (Quiz 17)
Ans. 1: Angiomatoid fibrous histiocytoma (AFH).
Ans. 2: Desmin, EMA, CD99, and CD68 (histiocytic marker).
Ans. 3: EWS1:CREB1 fusion as a result of t(2;22)(q33;q12) translocation.
Discussion | |  |
Angiomatoid fibrous histiocytoma (AFH) is an uncommon mesenchymal tumor of uncertain differentiation that has an intermediate malignant potential, with a rare propensity for metastasis. It occurs mostly in the superficial location, including the subcutis, and is histopathologically characterized by blood-filled pseudocystic spaces, a fibrous pseudo-capsule containing hemosiderin, a variable amount of polygonal and spindle cells, mitotic figures, and a peripheral rim of lymphoplasmacytic cells.[1] It frequently occurs in the extremities of young adults, similar to the present case. One-third cases might lack the cystic component and display a solid appearance.[1],[2],[3] Rare cases have been reported in deeper sites, such as the retroperitoneum, the lungs, the mediastinum, the vulva, and the ovary, especially with the help of ancillary tests.[4]
Immunohistochemically, more than 50% tumor expresses a variable amount of desmin, along with EMA, CD99/MIC2, and CD68.[1],[2],[3],[4] Furthermore, on molecular testing, most tumors display t (2; 22) (q33; q12) translocation, leading to EWSR1:CREB1 fusion, in more than 90% cases, followed by the less common t (12;22)(q12;q12), resulting in an EWSR1:ATF1 fusion and FUS: ATF1 fusion.[1],[4],[5]
The differential diagnosis includes a rhabdomyosarcoma, given desmin is expressed in the tumor cells. However, the lack of skeletal muscle specific markers, such as MyoD1 and myogenin, as noted in the present case, is helpful in ruling out rhabdomyosarcoma. Pleomorphic sarcoma and synovial sarcoma were ruled out in view of the afore-mentioned classic histopathological features, along with desmin positivity. Most cases of synovial sarcoma display diffuse TLE1, unlike the present tumor. Moreover, TLE1 is associated with low specificity.[6]
In conclusion, AFH should be suspected in a superficial solid-cystic tumor in young adults, especially in superficial location, displaying characteristic histopathological features, with variable desmin positivity. In cases with equivocal histopathological features and in tumors occurring at uncommon locations, it is desirable to demonstrate the specific genetic fusions or at least EWSR1 gene re-arrangement by fluorescence in situ hybridization. An exact diagnosis has treatment-associated implications as wide excision constitutes an optimal treatment, unlike in a high-grade sarcoma, where adjuvant treatments might be considered. | Figure 1: (a). MRI (coronal view) showing a well-defined heterogeneous, multi-lobulated mass along the anterolateral aspect of the left elbow joint [microscopic findings (b-d)]. (b). A well-defined, solid-cystic lesion in the dermis with blood-filled spaces. H and E, x 40. (c). Pseudocystic hemorrhagic spaces, including a space lined by cells. H and E, x 40. (d). Special stain (Prussian blue) highlighting many pigment-laden histiocytes lining the pseudo-capsule. H and E, x 10
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 | Figure 2: (a-b). Microscopic findings. (a). Solid area showing short spindle-shaped and polygonal cells arranged in a non-descript sheet-like pattern with subtle amphophilic stroma intervening blood and pigment-laden macrophages. (b). Higher magnification showing cells with round to polygonal shapes, vesicular chromatin, and scattered mitotic figures (dotted circle). H and E, x 400
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 | Figure 3: Tumor cells displaying significant desmin positivity. Diaminobenzidine (DAB), x 400
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Acknowledgements
We would like to thank the bone and soft tissue (BST) disease management group (DMG).
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.

References | |  |
1. | Rekhi B, Antonescu CR, Chen G. Angiomatoid fibrous histiocytoma. In: World Health Organization (WHO) classification of tumours editorial board, editors. World Health Organization Classification of Tumours. 5 th edition. Soft Tissue and Bone Tumours. Lyon, France: IARC Press; 2020. p. 271-3. |
2. | Fanburg-Smith JC, Miettinen M. Angiomatoid “malignant” fibrous histiocytoma: A clinicopathologic study of 158 cases and further exploration of the myoid phenotype. Hum Pathol 1999;30:1336-43. |
3. | Rekhi B, Adamane S, Ghodke K, Desai S, Jambhekar NA. Angiomatoid fibrous histiocytoma: Clinicopathological spectrum of five cases, including EWSR1-CREB1 positive result in a single case. Indian J Pathol Microbiol 2016;59:148-52.  [ PUBMED] [Full text] |
4. | Chen G, Folpe AL, Colby TV, Sittampalam K, Patey M, Chen MG, et al. Angiomatoid fibrous histiocytoma: Unusual sites and unusual morphology. Mod Pathol 2011;24:1560-70. |
5. | Rossi S, Szuhai K, Ijszenga M, Tanke HJ, Zanatta L, Sciot R, et al. EWSR1-CREB1 and EWSR1-ATF1 fusion genes in angiomatoid fibrous histiocytoma. Clin Cancer Res 2007;13:7322-8. |
6. | Kosemehmetoglu K, Vrana JA, Folpe AL. TLE1 expression is not specific for synovial sarcoma: A whole section study of 163 soft tissue and bone neoplasms. Mod Pathol 2009;22:872-8. |

Correspondence Address: Bindu Challa 410 W 10th Ave Columbus, Ohio – 43210 USA
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/ijpm.ijpm_1130_21

[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5] |
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